This is too rigid an account of what certain players can and can't do. Roles are well and good but this doesn't mean there is zero flexibility. Cole is "small". JoRo is "medium". Therefore one cannot cover the other? Not buying it. It's not useful to put players in boxes like this.
Its called picking a balanced defense.
Rotham can play tall or as a medium defender.
You look at style, experience and ability.
Just dont see Rotham competing directly with Cole for a spot.
Its like Waterman and Rioli vying / competing head to head for a forward spot. They arent.